{"paper":{"title":"One year of broadband radio monitoring of the enigmatic transient GRB 250702B reveals the evolution of the relativistic jet","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"A. J. Goodwin, Andrew Mummery, Arvind Balasubramanian, C. T. Christy, D. Eappachen, D. K. Sahu, Edo Berger, Enrico Ramirez-Ruiz, G. C. Anupama, Itai Sfaradi, James C. A. Miller-Jones, K. D. Alexander, Miguel P\\'erez-Torres, Raffaella Margutti, Ryan Chornock, Sjoert van Velzen, Tanmoy Laskar, Tarraneh Eftekhari, Varun Bhalerao, Yuhan Yao, Yvette Cendes","submitted_at":"2026-08-04T06:47:15Z","abstract_excerpt":"We present an extensive radio monitoring campaign of the unique extragalactic transient GRB 250702B, with observations spanning 0.65-233 GHz from 6-356 d (observer frame) post-discovery. The radio emission shows a smoothly evolving peaked synchrotron spectrum consistent with an adiabatic shock expanding into a stratified ambient medium ($n_e\\propto R^{-k}$; $k= 1.5-2$). We detect significant variability in the low frequency ($\\leq3$ GHz) light curves which we interpret as interstellar scintillation, placing an approximate bound on the blast wave image size of $1.2\\times10^{16}\\lesssim R_{\\perp"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2608.03205","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2608.03205/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}